Question

3. The service life of a battery used in a cardiac pacemaker is assumed to be normally distributed. A sample of twelve batteries is subjected to an accelerated life test by running them continuously at an elevated temperature until failure, and the following lifetimes (in hours) are obtained: 26.0, 26.3, 25.8, 24.8, 25.1, 27.4, 24.5, 26.2, 27.5, 25.9, 26.9, and 25.2. Test the hypothesis that the mean battery life exceeds 25 hours. a) State the null and alternative hypothesis. b) Compute the test statistics. c) Compute the P-value. d) State a conclusion e) Construct a 95% two-sided confidence interval on mean life in the accelerated test.

Answer 1